How to Tell Which Custom Shift Knobs Will Fit Your Car

October 31, 2012

Because most car gear shifters are standardized, most custom shift knobs, such as the Momo shift knob, will fit on most cars. However, that is not to say you should just set out today to replace your gear shifter without paying attention to the custom knob's dimensions. It is possible for a custom knob to be the wrong size for your car. Especially if it is foreign made or custom made, as in the case of a wood shift knob. Custom shift knobs usually come with their dimensions labeled, so to make sure that the knob you're looking at is going to fit your car, you should measure the thread and pitch of your gear shifter after you remove the current knob.

English or Metric

Since the measurements used by car manufacturers in different countries are in either the English or metric system, you will first have to determine where your car was manufactured. If it was made in a country that uses the metric system, you will use millimeters when you measure the tread and pitch of your gear shifter. If it was made in the United States, you will use inches.

How to Measure

First, measure the pitch of the shifter by using a ruler on the top to measure the diameter of the stick, then a caliper to determine the diameter of the stick plus the threads, then subtracting the ruler measurement from the caliper measurement. Half of that value is the depth of the threads. To measure the number of threads per unit distance, hold a ruler up to the stick and count the number of threads in one inch or centimeter.